Pre-eclampsia is a combination of raised blood pressure (hypertension) and protein in the urine (proteinuria). It is quite common, usually occurring after 20 weeks of pregnancy, affecting between 2 and 8 in 100 women during pregnancy. In most cases it is mild and has little effect on the pregnancy. However for 1 in 200 women, the effects are more serious. Severe pre-eclampsia can affect the mother by damaging the kidneys, liver and other organs and, in really severe cases, cause seizures and coma. There is often less fluid than normal around the baby and the placenta can be affected, restricting blood flow and nutrients necessary for the baby’s growth.
There has been great interest in tests aimed at predicting preeclampsia, though no single biomarker has been shown to sufficiently predict the disorder. Now, researchers from Hospital of Obstetrics and Gynaecology, Mexico state they have shown that levels of biomarkers in the blood of pregnant women can be used to predict which women are at risk of pre-eclampsia. The study is published in BJOG: An International Journal of Obstetrics and Gynaecology (BJOG).
Previous studies show that pre-eclampsia is thought to happen when the placenta isn’t working properly. Pre-eclampsia causes the flow of blood through the placenta to be reduced. This means that the baby won’t get enough oxygen and nutrients, which may restrict their growth. Pre-eclampsia usually happens in the second half of pregnancy, or shortly after the birth. It is most likely to develop after 27 weeks of pregnancy. Once identified, mothers can be monitored and treated. Often the baby will be delivered early by being induced or by caesarean section.
Earlier studies show that the usual test for pre-eclampsia are high blood pressure and protein in the urine. The patient is unusually able to tell if they have high blood pressure or protein in their urine and are advised to look out for the symptoms of pre-eclampsia. These are sudden, severe swelling of the face, hands or feet; severe headaches and/or vomiting; problems with vision, such as blurring or flashing before the eyes; severe pain just below the ribs and/or feeling generally unwell. As this condition can be severe biomarkers for pre-eclampsia risk have been investigated for many years.
The current study addresses the need to find a reliable way of screening women to find those at risk of pre-eclampsia. The team investigated several possible biomarkers including serum levels of asymmetric dimethylarginine (ADMA) and homocysteine (Hcy) which are known to be raised in several conditions, including pre-eclampsia.
The results showed that of the 252 women in their study (based at two hospitals) the 49 in the group who went on to develop pre-eclampsia had raised levels of ADMA and Hcy a month before onset of the condition. The levels of these two biomarkers were raised regardless of the eventual severity of the pre-eclampsia.
The team surmise that while for most of the women tested, the levels of ADMA and Hcy remained constant throughout pregnancy, these serum biomarkers were clearly raised a month before onset in women who went on to develop pre-eclampsia. They go on to conclude that of the other factors tested, obesity and low levels of folic acid at the start of the pregnancy (all the mothers received folic acid supplementation) were also independently linked to pre-eclampsia.